Method and apparatus for security gate gearing

ABSTRACT

A security gate drive mechanism is disclosed having a rotating shaft which rotates no more than a single rotation in order to provide through a linking mechanism, a driving force to move a security gate from a first position in which the security gate is essentially fully closed, to a second position in which the security gate is essentially fully open. A driving motor having a drive shaft rotating at much greater than one revolutions per minute, and a reduction gear contained in a reduction gear housing having an input shaft operatively connected to the drive shaft and an output shaft comprising or operatively connected to the rotating shaft, thus reducing the revolutions per minute of the drive shaft to a number of revolutions per minute suitable for operation of the security gate.

FIELD OF THE INVENTION

[0001] The present invention relates to the field of security gateoperating mechanism.

BACKGROUND OF THE INVENTION

[0002] It is well known to provide a security gate in which a drivemotor is used to operate a drive shaft, which is connected through areduction gear typically connected to a second reduction gear forexample by a pulley system. In this fashion the high rotational speed ofthe drive motor in RPM or, e.g., 1650 can be reduced to a speed ofsomething in the neighborhood of one RPM for the operating shaft of theoperating mechanism to rotate. This operating shaft is attachedtypically to a hinged operating arm that moves the security gate from afirst essentially fully closed position to an essentially fully openposition through a single revolution of the operating shaft or somewhatless that a single revolution. This same arrangement can also be usedwith a sliding security gate and the speed of the operating shaftreduced to several RPM. Using a single reduction gear has proved to benot feasible, since the size of the teeth in, e.g., a worm gearreduction gear would be so small that they would not be able to bear theload of swinging a large security gate from open to closed orvice-versa. This particular shortcoming of the prior art systems becomesexacerbated in the event that there is a obstacle blocking movement ofthe gate or for some other reason, e.g., accumulations of ice, snow ordirt or other debris on the gate, causing higher than normal torque tobe exerted on the reduction gear. This can cause jamming or worse damageto the reduction gear. Therefore, it has been found to be necessary touse at least two reduction gears, e.g., one with a 60:1 ration and onewith a 30:1 ratio. While this achieves the goal of reducing, e.g., amotor drive shaft rotation from e.g., 1650 RPM to 0.91 RPM, this can bea cumbersome and bulky arrangement.

[0003] The present invention solves the shortcomings of the prior artarrangements.

SUMMARY OF THE INVENTION

[0004] A security gate drive mechanism is disclosed having a rotatingshaft which rotates no more than a single rotation in order to providethrough a linking mechanism a driving force to move a security gate froma first position in which the security gate is essentially fully closedto a second position in which the security gate is essentially fullyopen, a driving motor having a drive shaft rotating at much greater thanone revolutions per minute, and a reduction gear, contained in areduction gear housing, having an input shaft operatively connected tothe drive shaft and an output shaft comprising or operatively connectedto the rotating shaft, for reducing the revolutions per minute of thedrive shaft to a number of revolutions per minute suitable for operationof the security gate, and including a gearing mechanism comprising: adrive shaft pulley fixedly attached to the drive shaft for rotation withthe rotation of the drive shaft; a reduction gear pulley having a largerdiameter than the drive shaft pulley and extending outside of aprojection of the reduction gear housing at least in a directiongenerally aligned with the axis of rotation of the reduction gear outputshaft; a reduction gear housing extension connected to the reductiongear housing and extending in the direction of the extension of thereduction gear output shaft from the reduction gear housing, and havingan opening through which extends the reduction gear output shaft; thereduction gear housing extension extending a sufficient distance to atleast place the respective extension of the reduction gear pulley withinthe projection of the reduction gear housing extension. The reductiongear housing extension may also have a bearing mounted in the openingadapted to rotationally support the reduction gear output shaft. Thereduction gear pulley together with the drive shaft pulley may provideat least a two to one reduction in the revolutions per minute on thedrive shaft to the revolutions per minute on the reduction gear inputshaft. The reduction gear pulley together with the drive shaft pulleyprovide at least a four to one reduction in the revolutions per minuteon the drive shaft to the revolutions per minute on the reduction gearinput shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005]FIG. 1 shows a partially cut-away plan view of a security gatedrive mechanism gearing arrangement according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] Turning now to FIG. 1 there is shown a security gate drivingmechanism gearing system 10 according to the present invention. Thegearing system can include a motor 12 and an operating shaft 14. Theoperating shaft 14 needs to be driven at a rotational speed of about oneRPM in order to rotate a pivoted arm (not shown) from a first positionto a second position, with the first position, e.g., corresponding tothe security gate being in one of a fully open or fully shut positionand the second position corresponding, e.g., to the security gate beingI the other of the fully open or fully shut positions.

[0007] The operating shaft 14 is connected to the motor 12 through areduction gear 20, contained within a housing 22, and comprising, e.g.,a worm gear reducing the rotational speed of an input shaft 24 in regardto the operating shaft 14 by, e.g., a 60:1 ratio. The input shaft 24 canbe driven by an input shaft pulley 26 which can be connected to a driveshaft pulley 28 connected to a drive shaft 30 of the motor 12 by apulley belt 40. The input shaft pulley 26 is sized to have, e.g., an 8:1speed reduction of the input shaft 24 vis-a-vis the motor drive shaft30, such that if the speed of the motor used were, e.g., 800 RPM and areduction gear with a 60:1 reduction ration along with, e.g., an 8:1reduction ration of the input shaft pulley 26 to the drive shaft pulley28 (i.e., an 8 inch diameter input shaft pulley 26 and a one inchdiameter drive shaft pulley 28) the resulting rotational rate of theoperating shaft can be reduced to 1.71 RPM.

[0008] In order to accomplish this, with the known arrangements for thereduction gear connected to the operating shaft 14 in the prior art (notshown) space must be provided for the enlarged input shaft pulley 26according to the present invention. In the past the input shaft pulleyand the drive shaft pulley were approximately the same size, e.g.,between one and two inches in diameter. At such size, any swinging arm(not shown) or sliding gate pulley/sprocket and chain (not shown). Inthe known art, for purposes of compactness, these items are generallyattached to the operating shaft 14 in as close a proximity to thereduction gear housing 22 as is mechanically possible.

[0009] In order to implement the present invention, the operating shaftis extended, as shown in FIG. 1 to extend through a housing extension44, in an opening therein provided with a bearing 46, which operates inconjunction with the existing bearing 42 contained in the reduction gear20 housing 22 as shown in partial cut-away view in FIG. 1, to supportthe extended operating shaft 14. It will be understood by those skilledin the art that the operating shaft 14 may already be of sufficientlength to not need an extension, and that if an extension is needed, theextension may be formed in a variety of known ways, e.g., threaded on tothe existing operation shaft 14, welded on to the existing operatingshaft 14 replacing the existing shaft 14 with one of longer length, etc.The extension 44 and extended length operating shaft 14 serve to placethe maximum radial displacement of the input shaft pulley (and ifnecessary the belt as seated on the pulley) at a minimum within alateral projection 50 of the extension 44. In this manner, the largerinput shaft pulley can be accommodated without interfering with either aswinging arm of sliding gate drive chain, or the like operativelyattached to the operating shaft. 14.

[0010] Those skilled in the art will appreciate that, depending upon themanner in which the operating shaft 14 is extended there may not be theopportunity to employ the bearing 42. If the extension is rigidlycoupled to the original shaft or the original shaft is replaces with alonger single piece shaft, then the intermediate bearing 42 may not beuseable. any warping of the operating shaft 14 could cause the failureof the intermediate bearing 42, dues to overloading and stress. In thisevent, the original end-plate 23 of the housing 22 of the reduction gear20, in which is seated the intermediate bearing 42, may simply bereplaced with a new end plate (not shown) that extends the length of thehousing 22 and in which is seated the bearing 46. On the other hand, ifa flexible or other coupling is used to attach an operating shaft 14extension which can accommodate an intermediate bearing without damagingit, then the extension housing 44 can simply be added on to the end ofthe reduction gear, as shown.

[0011] The present invention has been described in regard to a presentlypreferred embodiment of the invention but should not be limited only tothis preferred embodiment. Other modification and changes to the conceptof the presenting invention as embodied in the presently preferredembodiment will be understood by those skilled in the art to bepossible. Such modifications will be understood to be part of thepresent invention and included within the literal language of the claimsand/or equivalents of elements of the claims.

We claim:
 1. In a security gate drive mechanism having a rotating shaftwhich rotates at a relatively low rate of rotation in order to providethrough a linking mechanism a driving force to move a security gate froma first position in which the security gate is essentially fully closedto a second position in which the security gate is essentially fullyopen, a driving motor having a drive shaft rotating at much greater thanthe desired rotation rate, and a reduction gear, contained in areduction gear housing, having an input shaft operatively connected tothe drive shaft and an output shaft comprising or operatively connectedto the rotating shaft, for reducing the revolutions per minute of thedrive shaft to a number of revolutions per minute suitable for operationof the security gate, a gearing mechanism comprising: a drive shaftpulley fixedly attached to the drive shaft for rotation with therotation of the drive shaft; a reduction gear pulley having a largerdiameter than the drive shaft pulley and extending outside of aprojection of the reduction gear housing at least in a directiongenerally aligned with the axis of rotation of the reduction gear outputshaft; a reduction gear housing extension connected to the reductiongear housing and extending in the direction of the extension of thereduction gear output shaft from the reduction gear housing, and havingan opening through which extends the reduction gear output shaft; thereduction gear housing extension extending a sufficient distance to atleast place the respective extension of the reduction gear pulley withinthe projection of the reduction gear housing extension.
 2. The apparatusof claim 1 wherein the reduction gear housing extension has a bearingmounted in the opening adapted to rotationally support the reductiongear output shaft.
 3. The apparatus of claim 1 wherein the reductiongear pulley together with the drive shaft pulley provide at least a twoto one reduction in the revolutions per minute on the drive shaft to therevolutions per minute on the reduction gear input shaft.
 4. Theapparatus of claim 2 wherein the reduction gear pulley together with thedrive shaft pulley provide at least a two to one reduction in therevolutions per minute on the drive shaft to the revolutions per minuteon the reduction gear input shaft.
 5. The apparatus of claim 1 whereinthe reduction gear pulley together with the drive shaft pulley provideat least a four to one reduction in the revolutions per minute on thedrive shaft to the revolutions per minute on the reduction gear inputshaft.
 6. The apparatus of claim 2 wherein the reduction gear pulleytogether with the drive shaft pulley provide at least a four to onereduction in the revolutions per minute on the drive shaft to therevolutions per minute on the reduction gear input shaft.
 7. In asecurity gate operating mechanism having a drive motor operativelyconnected to an operating shaft through a reduction gear contained in areduction gear housing, wherein the operating shaft is positioned andoperatively connected to the security gate through a linking mechanismto move the security gate from a first position to a second positionthrough rotary motion of the operating shaft, and wherein therevolutions per minute of the drive motor, without reduction, wouldrotate the operating shaft between a first position and a secondposition of the operating shaft corresponding to the security gate firstand second positions, in an unacceptably fast manner, and wherein thelinking mechanism extends generally perpendicularly to the axis ofrotation of the operating shaft and generally parallel to a projectionof the reduction gear housing in a first plane perpendicular to the axisof rotation of the operating shaft, a gearing mechanism comprising: areduction gear input pulley that is larger than a drive shaft pulley andoperatively connected to the drive shaft pulley, and wherein thereduction gear input pulley extends beyond the projection of thereduction gear housing; a reduction gear housing extension attached tothe reduction gear housing in the vicinity of the operating shaft,whereby the linking mechanism extending generally parallel to aprojection of the reduction gear housing extension is in a second planeperpendicular to the access of rotation of the operating shaft, anddisplaced from the first plane a distance sufficient to accommodate theincreased size of the reduction gear input pulley.
 8. The apparatus ofclaim 7 wherein the reduction gear housing extension has a bearingmounted in an opening through the reduction gear housing extensionadapted to rotationally support the reduction gear output shaft.
 9. Theapparatus of claim 7 wherein the reduction gear pulley together with thedrive shaft pulley provide at least a two to one reduction in therevolutions per minute on the drive shaft to the revolutions per minuteon the reduction gear input shaft.
 10. The apparatus of claim 8 whereinthe reduction gear pulley together with the drive shaft pulley provideat least a two to one reduction in the revolutions per minute on thedrive shaft to the revolutions per minute on the reduction gear inputshaft.
 11. The apparatus of claim 7 wherein the reduction gear pulleytogether with the drive shaft pulley provide at least a four to onereduction in the revolutions per minute on the drive shaft to therevolutions per minute on the reduction gear input shaft.
 12. Theapparatus of claim 8 wherein the reduction gear pulley together with thedrive shaft pulley provide at least a four to one reduction in therevolutions per minute on the drive shaft to the revolutions per minuteon the reduction gear input shaft.
 13. A method of operating a securitygate having a drive motor operatively connected to an operating shaftthrough a reduction gear contained in a reduction gear housing, whereinthe operating shaft is positioned and operatively connected to thesecurity gate through a linking mechanism to move the security gate froma first position to a second position through rotary motion of theoperating shaft, and wherein the revolutions per minute of the drivemotor, without reduction, would rotate the operating shaft between afirst position and a second position of the operating shaft,corresponding to the security gate first and second positions, in anunacceptably fast manner, and wherein the linking mechanism extendsgenerally perpendicularly to the axis of rotation of the operating shaftand generally parallel to a projection of the reduction gear housing ina first plane perpendicular to the axis of rotation of the operatingshaft, comprising the steps of: reducing the rotational speed of themotor drive shaft input to the reduction gear input shaft utilizing areduction gear input pulley that is larger than a drive shaft pulley andoperatively connected to the drive shaft pulley, and wherein thereduction gear input pulley extends beyond the projection of thereduction gear housing; extending the reduction gear housing with anattached extension in the vicinity of the operating shaft, whereby thelinking mechanism is enabled to clear the reduction gear input pulley inoperation.
 14. The method of claim 13 including rotationally support thereduction gear output shaft with a bearing mounted in an opening throughthe attached extension.
 15. The method of claim 13 including provide atleast a two to one reduction in the revolutions per minute on the driveshaft to the revolutions per minute on the reduction gear input shaft.16. The apparatus of claim 14 including providing at least a two to onereduction in the revolutions per minute on the drive shaft to therevolutions per minute on the reduction gear input shaft.
 17. Theapparatus of claim 13 including providing at least a four to onereduction in the revolutions per minute on the drive shaft to therevolutions per minute on the reduction gear input shaft.
 18. Theapparatus of claim 14 including providing at least a four to onereduction in the revolutions per minute on the drive shaft to therevolutions per minute on the reduction gear input shaft.
 19. In asecurity gate drive mechanism having a rotating shaft which rotates inorder to provide through a linking mechanism a driving force to move asecurity gate from a first position in which the security gate isessentially fully closed to a second position in which the security gateis essentially fully open, a driving motor having a drive shaft rotatingat much greater than one revolutions per minute, and a reduction gear,contained in a reduction gear housing, having an input shaft operativelyconnected to the drive shaft and an output shaft comprising oroperatively connected to the rotating shaft, for reducing therevolutions per minute of the drive shaft to a number of revolutions perminute of the operating shaft suitable for operation of the securitygate, a gearing mechanism comprising: a drive shaft pulley fixedlyattached to the drive shaft for rotation with the rotation of the driveshaft; a reduction gear pulley having a larger diameter than the driveshaft pulley and extending outside of a projection of the reduction gearhousing at least in a direction generally aligned with the axis ofrotation of the reduction gear output shaft; a reduction gear housingextension means for extending in the direction of the extension of thereduction gear output shaft from the reduction gear housing a sufficientdistance to at least place the respective extension of the reductiongear pulley within a projection of the reduction gear housing extension.20. The apparatus of claim 19 wherein the reduction gear housingextension means has a bearing mounted in the opening adapted torotationally support the reduction gear output shaft.